Three-dimensional vertical NAND strings having one bit per cell are disclosed in an article by T. Endoh, et. al., titled “Novel Ultra High Density Memory With A Stacked-Surrounding Gate Transistor (S-SGT) Structured Cell”, IEDM Proc. (2001) 33-36. An epitaxial channel portion can be employed as a portion of a channel for a vertical NAND string controlled by one or more select gate electrodes. Deformation of the epitaxial channel portion during a manufacturing process step can degrade performance of the memory device. Thus, a properly shaped epitaxial channel portion and a method of forming the same are desired.